Metal Roof Gutters: Profiles and Metals
The gutter has to match the roof in two ways. It has to catch the flow, and its metal has to get along with the roof metal. Here are the main choices.
Seamless Aluminum K-Style
Seamless gutters are formed from a coil into one piece per run, so the only joints are at corners and outlets. The K-style shape, flat-backed with an ogee front, is the standard on American houses. Most homes use the 5-inch size, and homes with heavy rain or large roofs may need 6-inch, which adds about $1 to $2 per foot. Under a metal roof, ask for a 6-inch price as well. Faster runoff off smooth panels is the reason gutter installers give for sizing up. Coil thickness matters too. The industry standard for houses is 0.027 inch, and 0.032 inch uses about 18% more metal for a stiffer gutter. Aluminum gutters run about $10 to $20 per linear foot installed nationally and last about 20 to 30 years.
Half-Round Gutters
Half-round gutters have a semicircular trough and hang on straps with spring clips or on special brackets, not hidden hangers. They cost about $1 to $2 more per foot than K-style. They suit a house where the gutter is meant to show, and they're the usual shape for copper.
Copper Gutters
Copper gutters are the right call under any copper roof, bay or flashing, and they're often chosen to match copper accents. They run about $25 to $40 per linear foot installed, with a rated life of 50 to 100 years. The Copper Development Association's handbook hangs them on brass or copper brackets no more than 36 inches apart in places without snow, with braces made of 20-ounce copper. Copper weathers to brown and then green along with the roof. They're the gutter to use under copper; aluminum below copper corrodes.
Box and Built-In Gutters
Some older houses and commercial buildings have gutters built into the roof edge or cornice: a wood trough lined with sheet metal. The CDA handbook says the lining has to be free to move, not fit tight. Its inner edge should finish at least 2 inches above the outer edge so an overflow spills outward, not into the wall. Lining sheets run 10 feet at most, joined with 1½-inch lapped, riveted and soldered seams. Relining is metalwork, not gutter hanging, so ask whether the contractor solders.
Gutter Guards and Edge Trim on Metal Roofs
Guards cost about $15 to $45 per linear foot installed nationally. Under a metal roof, ask how the guard attaches. It shouldn't be screwed through the panels or tucked under them unless the panel maker's instructions allow it. The eave trim and drip edge are part of the roof system, and the code points to the maker's instructions for how they're fastened. The CDA handbook's rule applies to every gutter: it has to be hung so it intercepts the water coming off the roof.
Why Columbia homeowners call Columbia Metal Roofs
- A free on-site measure and a written quote
- Panel type, steel gauge and paint system spelled out before you sign
- Ask who pulls the roofing permit: it goes in the scope
- Your request goes to one independent metal roofer, not a list
- No fee to the property owner for the referral
Metal Roof Gutters and Columbia Rainfall
Columbia gets about 45 inches of rain a year at the airport. On about 13 days a year, an inch or more falls in a day. July is the wettest month at 5.35 inches, and South Carolina averages 45 to 70 thunderstorm days a year. A metal roof sheds that water fast because the surface is smooth. On a long, steep run, water can shoot past a 5-inch gutter that worked fine under shingles. Valleys concentrate it further.
What usually fixes overshoot and overflow:
Wider gutters
Six-inch K-style holds more and sits farther out under the eave.More downspouts
Each downspout costs about $30 to $75 installed nationally. A long run with a single downspout can't drain fast enough in a downpour.Diverters at valleys
A valley can dump a roof's worth of water into a few feet of gutter.Splash blocks or extensions
These cost about $10 to $50 per downspout. They move water away from the foundation.Hangers set for the roof edge
The gutter's position under the eave decides whether fast water lands in it or over it.
Metal Roof Gutters: Matching Metals, Fasteners and Lifespan
The Metal Construction Association lists aluminum accessories such as fasteners, curbs and clamps as compatible with Galvalume, so aluminum gutters under a Galvalume roof are a normal pairing. Copper anywhere upslope is the exception; the copper roofing page explains why. Use aluminum or stainless fasteners with aluminum gutters, and copper or brass hangers with copper gutters. A zinc-coated screw in aluminum is a small anode in a large cathode, and the zinc corrodes.
Lifespans don't line up either. National cost guides give aluminum gutters 20 to 30 years and steel 20 to 50, against 50 to 100 for copper. A metal roof is built to last longer than aluminum gutters (see metal roof installation for roof lifespans), so the gutters may need replacing first. If yours are near that age, price new ones in the same visit as any roof work.
If the roof is being replaced, ask whether the gutters come off and go back up, or get replaced at the same time. The eave trim on a new metal roof can change where the water lands, and old gutters hung for shingles may sit in the wrong spot.
Metal Roof Gutters Estimate Checklist
Size and profile
5- or 6-inch, K-style or half-round, and coil thickness (0.027 or 0.032 inch).Downspouts
Count, size and where each one discharges.Hangers
Type, spacing and what they fasten into.Metal match
Gutter metal and fastener metal against the roof metal.Valley diverters and guards
Included or extra.Old gutter removal and disposal
Included or extra.Low-roof sections
Porch and addition roofs dump water at one edge. See low slope metal roof.